One of the challenges of dealing with people is that given almost exactly the same information they can leap to two completely different conclusions. I've just sat opened jawed in front of the Republican Candidate debate on two successive questions
First was "Do you accept Evolution"
Second was "Do you accept Global Warming"
On the first one a candidate (don't know the name I'm afraid) said the great phrase "some people might want to believe that they come from primates, however far that gets them", this was then followed up on the next question by "we have to accept what the scientists tell us".... sheer genius.
Now what has this to do with SOA? Well simply put its all about communication and expectation. If you have two services that look similar it isn't enough to just assume that they are because the reference points for the developers might have been completely different, one might be paranoid about security and require a million hoops, while the other doesn't care about reliability so runs it off their mobile phone. Equally when dealing with consumers you shouldn't assume that they are doing the right thing, or maybe even know what they are doing.
The Republican candidates give a great example as to why its good to validate and check, and cross check. Its just a shame the guy asking the questions didn't spot the glaring inconsistency and allowed what can only be called an error condition to pass un-noticed with who knows what unintended consequences.
Check and verify, the people might be dumber than you think.